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-rw-r--r--lib/mnesia/src/mnesia_locker.erl181
1 files changed, 107 insertions, 74 deletions
diff --git a/lib/mnesia/src/mnesia_locker.erl b/lib/mnesia/src/mnesia_locker.erl
index de4811f8e4..a22c95d454 100644
--- a/lib/mnesia/src/mnesia_locker.erl
+++ b/lib/mnesia/src/mnesia_locker.erl
@@ -1,7 +1,7 @@
%%
%% %CopyrightBegin%
%%
-%% Copyright Ericsson AB 1996-2011. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2012. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
@@ -66,7 +66,7 @@
-record(queue, {oid, tid, op, pid, lucky}).
-%% mnesia_held_locks: contain {Oid, Op, Tid} entries (bag)
+%% mnesia_held_locks: contain {Oid, MaxLock, [{Op, Tid}]} entries
-define(match_oid_held_locks(Oid), {Oid, '_', '_'}).
%% mnesia_tid_locks: contain {Tid, Oid, Op} entries (bag)
-define(match_oid_tid_locks(Tid), {Tid, '_', '_'}).
@@ -83,7 +83,7 @@ start() ->
init(Parent) ->
register(?MODULE, self()),
process_flag(trap_exit, true),
- ?ets_new_table(mnesia_held_locks, [bag, private, named_table]),
+ ?ets_new_table(mnesia_held_locks, [ordered_set, private, named_table]),
?ets_new_table(mnesia_tid_locks, [bag, private, named_table]),
?ets_new_table(mnesia_sticky_locks, [set, private, named_table]),
?ets_new_table(mnesia_lock_queue, [bag, private, named_table, {keypos, 2}]),
@@ -235,10 +235,17 @@ loop(State) ->
loop(State)
end.
-set_lock(Tid, Oid, Op) ->
- ?dbg("Granted ~p ~p ~p~n", [Tid,Oid,Op]),
- ?ets_insert(mnesia_held_locks, {Oid, Op, Tid}),
- ?ets_insert(mnesia_tid_locks, {Tid, Oid, Op}).
+set_lock(Tid, Oid, Op, []) ->
+ ?ets_insert(mnesia_tid_locks, {Tid, Oid, Op}),
+ ?ets_insert(mnesia_held_locks, {Oid, Op, [{Op, Tid}]});
+set_lock(Tid, Oid, read, [{Oid, Prev, Items}]) ->
+ ?ets_insert(mnesia_tid_locks, {Tid, Oid, read}),
+ ?ets_insert(mnesia_held_locks, {Oid, Prev, [{read, Tid}|Items]});
+set_lock(Tid, Oid, write, [{Oid, _Prev, Items}]) ->
+ ?ets_insert(mnesia_tid_locks, {Tid, Oid, write}),
+ ?ets_insert(mnesia_held_locks, {Oid, write, [{write, Tid}|Items]});
+set_lock(Tid, Oid, Op, undefined) ->
+ set_lock(Tid, Oid, Op, ?ets_lookup(mnesia_held_locks, Oid)).
%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Acquire locks
@@ -261,14 +268,14 @@ try_lock(Tid, Op, Pid, Oid) ->
try_lock(Tid, Op, SimpleOp, Lock, Pid, Oid) ->
case can_lock(Tid, Lock, Oid, {no, bad_luck}) of
- yes ->
- Reply = grant_lock(Tid, SimpleOp, Lock, Oid),
+ {yes, Default} ->
+ Reply = grant_lock(Tid, SimpleOp, Lock, Oid, Default),
reply(Pid, Reply);
- {no, Lucky} ->
+ {{no, Lucky},_} ->
C = #cyclic{op = SimpleOp, lock = Lock, oid = Oid, lucky = Lucky},
?dbg("Rejected ~p ~p ~p ~p ~n", [Tid, Oid, Lock, Lucky]),
reply(Pid, {not_granted, C});
- {queue, Lucky} ->
+ {{queue, Lucky},_} ->
?dbg("Queued ~p ~p ~p ~p ~n", [Tid, Oid, Lock, Lucky]),
%% Append to queue: Nice place for trace output
?ets_insert(mnesia_lock_queue,
@@ -277,16 +284,16 @@ try_lock(Tid, Op, SimpleOp, Lock, Pid, Oid) ->
?ets_insert(mnesia_tid_locks, {Tid, Oid, {queued, Op}})
end.
-grant_lock(Tid, read, Lock, Oid = {Tab, Key})
+grant_lock(Tid, read, Lock, Oid = {Tab, Key}, Default)
when Key /= ?ALL, Tab /= ?GLOBAL ->
case node(Tid#tid.pid) == node() of
true ->
- set_lock(Tid, Oid, Lock),
+ set_lock(Tid, Oid, Lock, Default),
{granted, lookup_in_client};
false ->
try
Val = mnesia_lib:db_get(Tab, Key), %% lookup as well
- set_lock(Tid, Oid, Lock),
+ set_lock(Tid, Oid, Lock, Default),
{granted, Val}
catch _:_Reason ->
%% Table has been deleted from this node,
@@ -296,19 +303,19 @@ grant_lock(Tid, read, Lock, Oid = {Tab, Key})
{not_granted, C}
end
end;
-grant_lock(Tid, {ix_read,IxKey,Pos}, Lock, Oid = {Tab, _}) ->
+grant_lock(Tid, {ix_read,IxKey,Pos}, Lock, Oid = {Tab, _}, Default) ->
try
Res = ix_read_res(Tab, IxKey,Pos),
- set_lock(Tid, Oid, Lock),
+ set_lock(Tid, Oid, Lock, Default),
{granted, Res, [?ALL]}
catch _:_ ->
{not_granted, {no_exists, Tab, {index, [Pos]}}}
end;
-grant_lock(Tid, read, Lock, Oid) ->
- set_lock(Tid, Oid, Lock),
+grant_lock(Tid, read, Lock, Oid, Default) ->
+ set_lock(Tid, Oid, Lock, Default),
{granted, ok};
-grant_lock(Tid, write, Lock, Oid) ->
- set_lock(Tid, Oid, Lock),
+grant_lock(Tid, write, Lock, Oid, Default) ->
+ set_lock(Tid, Oid, Lock, Default),
granted.
%% 1) Impose an ordering on all transactions favour old (low tid) transactions
@@ -318,55 +325,40 @@ grant_lock(Tid, write, Lock, Oid) ->
%% 3) TabLocks is the problem :-) They should not starve and not deadlock
%% handle tablocks in queue as they had locks on unlocked records.
-can_lock(Tid, read, {Tab, Key}, AlreadyQ) when Key /= ?ALL ->
- %% The key is bound, no need for the other BIF
- Oid = {Tab, Key},
- ObjLocks = ?ets_match_object(mnesia_held_locks, {Oid, write, '_'}),
- TabLocks = ?ets_match_object(mnesia_held_locks, {{Tab, ?ALL}, write, '_'}),
- check_lock(Tid, Oid, ObjLocks, TabLocks, yes, AlreadyQ, read);
+can_lock(Tid, read, Oid = {Tab, Key}, AlreadyQ) when Key /= ?ALL ->
+ ObjLocks = ?ets_lookup(mnesia_held_locks, Oid),
+ TabLocks = ?ets_lookup(mnesia_held_locks, {Tab, ?ALL}),
+ {check_lock(Tid, Oid,
+ filter_write(ObjLocks),
+ filter_write(TabLocks),
+ yes, AlreadyQ, read),
+ ObjLocks};
can_lock(Tid, read, Oid, AlreadyQ) -> % Whole tab
Tab = element(1, Oid),
ObjLocks = ?ets_match_object(mnesia_held_locks, {{Tab, '_'}, write, '_'}),
- check_lock(Tid, Oid, ObjLocks, [], yes, AlreadyQ, read);
+ {check_lock(Tid, Oid, ObjLocks, [], yes, AlreadyQ, read), undefined};
-can_lock(Tid, write, {Tab, Key}, AlreadyQ) when Key /= ?ALL ->
- Oid = {Tab, Key},
+can_lock(Tid, write, Oid = {Tab, Key}, AlreadyQ) when Key /= ?ALL ->
ObjLocks = ?ets_lookup(mnesia_held_locks, Oid),
TabLocks = ?ets_lookup(mnesia_held_locks, {Tab, ?ALL}),
- check_lock(Tid, Oid, ObjLocks, TabLocks, yes, AlreadyQ, write);
+ {check_lock(Tid, Oid, ObjLocks, TabLocks, yes, AlreadyQ, write), ObjLocks};
can_lock(Tid, write, Oid, AlreadyQ) -> % Whole tab
Tab = element(1, Oid),
ObjLocks = ?ets_match_object(mnesia_held_locks, ?match_oid_held_locks({Tab, '_'})),
- check_lock(Tid, Oid, ObjLocks, [], yes, AlreadyQ, write).
+ {check_lock(Tid, Oid, ObjLocks, [], yes, AlreadyQ, write), undefined}.
+
+filter_write([{_, read, _}]) -> [];
+filter_write(Res) -> Res.
%% Check held locks for conflicting locks
-check_lock(Tid, Oid, [Lock | Locks], TabLocks, X, AlreadyQ, Type) ->
- case element(3, Lock) of
- Tid ->
- check_lock(Tid, Oid, Locks, TabLocks, X, AlreadyQ, Type);
- WaitForTid ->
- Queue = allowed_to_be_queued(WaitForTid,Tid),
- if Queue == true ->
- check_lock(Tid, Oid, Locks, TabLocks, {queue, WaitForTid}, AlreadyQ, Type);
- Tid#tid.pid == WaitForTid#tid.pid ->
- dbg_out("Spurious lock conflict ~w ~w: ~w -> ~w~n",
- [Oid, Lock, Tid, WaitForTid]),
- %% Test..
- {Tab, _Key} = Oid,
- HaveQ = (ets:lookup(mnesia_lock_queue, Oid) /= [])
- orelse (ets:lookup(mnesia_lock_queue,{Tab,?ALL}) /= []),
- if
- HaveQ ->
- {no, WaitForTid};
- true ->
- check_lock(Tid,Oid,Locks,TabLocks,{queue,WaitForTid},AlreadyQ,Type)
- end;
- %%{no, WaitForTid}; Safe solution
- true ->
- {no, WaitForTid}
- end
+check_lock(Tid, Oid, [{_, _, Lock} | Locks], TabLocks, _X, AlreadyQ, Type) ->
+ case can_queue(Lock, Tid, Oid, _X) of
+ {no, _} = Res ->
+ Res;
+ Res ->
+ check_lock(Tid, Oid, Locks, TabLocks, Res, AlreadyQ, Type)
end;
check_lock(_, _, [], [], X, {queue, bad_luck}, _) ->
@@ -375,8 +367,7 @@ check_lock(_, _, [], [], X, {queue, bad_luck}, _) ->
check_lock(_, _, [], [], X = {queue, _Tid}, _AlreadyQ, _) ->
X;
-check_lock(Tid, Oid, [], [], X, AlreadyQ, Type) ->
- {Tab, Key} = Oid,
+check_lock(Tid, Oid = {Tab, Key}, [], [], X, AlreadyQ, Type) ->
if
Type == write ->
check_queue(Tid, Tab, X, AlreadyQ);
@@ -403,6 +394,26 @@ check_lock(Tid, Oid, [], [], X, AlreadyQ, Type) ->
check_lock(Tid, Oid, [], TabLocks, X, AlreadyQ, Type) ->
check_lock(Tid, Oid, TabLocks, [], X, AlreadyQ, Type).
+can_queue([{_Op, Tid}|Locks], Tid, Oid, Res) ->
+ can_queue(Locks, Tid, Oid, Res);
+can_queue([{Op, WaitForTid}|Locks], Tid, Oid = {Tab, _}, _) ->
+ case allowed_to_be_queued(WaitForTid,Tid) of
+ true when Tid#tid.pid == WaitForTid#tid.pid ->
+ dbg_out("Spurious lock conflict ~w ~w: ~w -> ~w~n",
+ [Oid, Op, Tid, WaitForTid]),
+ HaveQ = (ets:lookup(mnesia_lock_queue, Oid) /= [])
+ orelse (ets:lookup(mnesia_lock_queue,{Tab,?ALL}) /= []),
+ case HaveQ of
+ true -> {no, WaitForTid};
+ false -> can_queue(Locks, Tid, Oid, {queue, WaitForTid})
+ end;
+ true ->
+ can_queue(Locks, Tid, Oid, {queue, WaitForTid});
+ false ->
+ {no, WaitForTid}
+ end;
+can_queue([], _, _, Res) -> Res.
+
%% True if WaitForTid > Tid -> % Important order
allowed_to_be_queued(WaitForTid, Tid) ->
case get(pid_sort_order) of
@@ -456,14 +467,14 @@ set_read_lock_on_all_keys(Tid, From, Tab, IxKey, Pos) ->
Op = {ix_read,IxKey, Pos},
Lock = read,
case can_lock(Tid, Lock, Oid, {no, bad_luck}) of
- yes ->
- Reply = grant_lock(Tid, Op, Lock, Oid),
+ {yes, Default} ->
+ Reply = grant_lock(Tid, Op, Lock, Oid, Default),
reply(From, Reply);
- {no, Lucky} ->
+ {{no, Lucky},_} ->
C = #cyclic{op = Op, lock = Lock, oid = Oid, lucky = Lucky},
?dbg("Rejected ~p ~p ~p ~p ~n", [Tid, Oid, Lock, Lucky]),
reply(From, {not_granted, C});
- {queue, Lucky} ->
+ {{queue, Lucky},_} ->
?dbg("Queued ~p ~p ~p ~p ~n", [Tid, Oid, Lock, Lucky]),
%% Append to queue: Nice place for trace output
?ets_insert(mnesia_lock_queue,
@@ -520,14 +531,24 @@ release_locks([]) ->
release_lock({Tid, Oid, {queued, _}}) ->
?ets_match_delete(mnesia_lock_queue, #queue{oid=Oid, tid = Tid, op = '_',
pid = '_', lucky = '_'});
-release_lock({Tid, Oid, Op}) ->
- if
- Op == write ->
- ?ets_delete(mnesia_held_locks, Oid);
- Op == read ->
- ets:delete_object(mnesia_held_locks, {Oid, Op, Tid})
+release_lock({_Tid, Oid, write}) ->
+ ?ets_delete(mnesia_held_locks, Oid);
+release_lock({Tid, Oid, read}) ->
+ case ?ets_lookup(mnesia_held_locks, Oid) of
+ [{Oid, Prev, Locks0}] ->
+ case remove_tid(Locks0, Tid, []) of
+ [] -> ?ets_delete(mnesia_held_locks, Oid);
+ Locks -> ?ets_insert(mnesia_held_locks, {Oid, Prev, Locks})
+ end;
+ [] -> ok
end.
+remove_tid([{_Op, Tid}|Ls], Tid, Acc) ->
+ remove_tid(Ls,Tid, Acc);
+remove_tid([Keep|Ls], Tid, Acc) ->
+ remove_tid(Ls,Tid, [Keep|Acc]);
+remove_tid([], _, Acc) -> Acc.
+
rearrange_queue([{_Tid, {Tab, Key}, _} | Locks]) ->
if
Key /= ?ALL->
@@ -592,18 +613,18 @@ try_waiter({queue, Oid, Tid, Op, ReplyTo, _}) ->
try_waiter(Oid, Op, SimpleOp, Lock, ReplyTo, Tid) ->
case can_lock(Tid, Lock, Oid, {queue, bad_luck}) of
- yes ->
+ {yes, Default} ->
%% Delete from queue: Nice place for trace output
?ets_match_delete(mnesia_lock_queue,
#queue{oid=Oid, tid = Tid, op = Op,
pid = ReplyTo, lucky = '_'}),
- Reply = grant_lock(Tid, SimpleOp, Lock, Oid),
+ Reply = grant_lock(Tid, SimpleOp, Lock, Oid, Default),
reply(ReplyTo,Reply),
locked;
- {queue, _Why} ->
+ {{queue, _Why}, _} ->
?dbg("Keep ~p ~p ~p ~p~n", [Tid, Oid, Lock, _Why]),
queued; % Keep waiter in queue
- {no, Lucky} ->
+ {{no, Lucky}, _} ->
C = #cyclic{op = SimpleOp, lock = Lock, oid = Oid, lucky = Lucky},
verbose("** WARNING ** Restarted transaction, possible deadlock in lock queue ~w: cyclic = ~w~n",
[Tid, C]),
@@ -1116,11 +1137,23 @@ rec_requests([], _Oid, _Store) ->
get_held_locks() ->
?MODULE ! {get_table, self(), mnesia_held_locks},
- receive {mnesia_held_locks, Locks} -> Locks end.
+ Locks = receive {mnesia_held_locks, Ls} -> Ls after 5000 -> [] end,
+ rewrite_locks(Locks, []).
+
+rewrite_locks([{Oid, _, Ls}|Locks], Acc0) ->
+ Acc = rewrite_locks(Ls, Oid, Acc0),
+ rewrite_locks(Locks, Acc);
+rewrite_locks([], Acc) ->
+ lists:reverse(Acc).
+
+rewrite_locks([{Op, Tid}|Ls], Oid, Acc) ->
+ rewrite_locks(Ls, Oid, [{Oid, Op, Tid}|Acc]);
+rewrite_locks([], _, Acc) ->
+ Acc.
get_lock_queue() ->
?MODULE ! {get_table, self(), mnesia_lock_queue},
- Q = receive {mnesia_lock_queue, Locks} -> Locks end,
+ Q = receive {mnesia_lock_queue, Locks} -> Locks after 5000 -> [] end,
[{Oid, Op, Pid, Tid, WFT} || {queue, Oid, Tid, Op, Pid, WFT} <- Q].
do_stop() ->
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-27 20:16:17 +0000